Background: Exercise can counteract the negative effects of stress, but variations in exercise protocols and intensities have generated different results. The purpose of this study was to investigate the effect of immobilization stress on cognitive performance and the moderating role of exercise.

Materials and Methods: In this experimental study, adult Albino-Wistar rats were randomly assigned to 5 groups. The animals underwent immobilization stress (2 hours per day×7 day), exercise (30 minutes per day×7 day), or no intervention. The rats were trained and tested using Morris water maze.

Results: The control group had better performance than the stress group in acquisition (p<0.01) and recall (p<0.05) in Morris water maze. There was not a significant difference between exercise-stress and control groups in water maze performance. Stress increased corticosterone levels (p<0.001), but exercise had a significant effect on decrement of corticosteron levels (p<0.001). Also, despite the absence of a significant difference between sham and exercise groups in the acquisition stage, the exercise group had a better performance in the recall stage (p<0.05).

Conclusion: Immobilization stress can impair acquisition and mild exercise has a protective effect against stress-induced negative effects. Corticosterone may be a major mediator in the protective effect of exercise against stress-induced cognitive impairment. In addition, the role of exercise in retrieval of past experiences is more prominent than their acquisition.

Background: Due to high risk of physical inactivity in children with autism spectrum disorders (ASD) and its adverse consequences, evaluating their level of physical activity (PA) using accelerometry and investigating its relation with age and severity of the disorder are integral.

Materials and Methods: Fifty two boys and sixteen girls aged 7-14 years -from autism schools in Tehran- participated in current cross sectional study. Level of daily PA was evaluated for seven consecutive days using accelerometers. Autism severity was also assessed in the areas of communication, sociability, sensory and cognitive awareness, and health and physical behavior using Autism Treatment Evaluation Checklist (ATEC).

Results: On the whole 91 percent of participants encountered low level of PA. Girls were remarkably less active than boys and were more inactive. Level of PA significantly reduced as they aged. Level of PA was adversely and significantly correlated with autism severity in the area of sensory and cognitive awareness. Moreover, level of vigorous PA was adversely and significantly correlated with total autism severity. Finally, age, sex, and sensory and cognitive awareness were partially predictors of PA.

Conclusion: It appears that children with HFA are physically inactive and considerably engage in more sedentary activities as they age. Age and gender can be considered as physical activity determinants among this population.